[rdorman]

Just the basic autolite 25. They also have a platinum, double platinum and xtreme AP25, APP25 AND XP25 respectively. Never had any problems with the basic autolite but I don't see why the upgraded plugs would be a problem either. If you are not getting sooty carbon deposits on the insulator around the center electrode, it is hot enough. If it has a speckled appearence, it is to hot. Be VERY careful increasing the temp of the plug (IE 26). Generally, the more performance oriented the colder.